This invention relates to a flexible connector for a screening machine and more particularly to modular flexible connectors which can be assembled to provide connectors of different desired lengths, facilitated replacement of worn areas, and provide an overall increase in flexibility.
Screening machines are used for sizing, sifting or deliquifying a variety of comminuted materials such as food products, abrasives, face and dental powders, pigments, pharmaceuticals, fillers, spirit distillers, mash, clays and clay slips, spices, starch, sugar and many other types of materials. The material to be treated travels from a feed chute, which is generally fixed, through a flexible connector onto a screen surface located beneath the feed chute. The connector is usually a flexible tube of generally circular cross-section which is secured at one end in communication with the feed chute. The opposite end of the connector is secured to the top cover of the frame or box which supports the screen. Similar connectors may be provided below the screen to carry particles after they have been screened.
The screening process generally requires that the screen be gyrated or shaken in a plane transverse to the axis of connection between the feed chute and the screen, and the connector must be flexible to accommodate this movement which is lateral to it. In addition, because the feed chute and the frame are not always in vertical alignment and because the surface of the screen is usually not horizontal, the flexible connector usually bends between its ends. It is known to provide corrugations in flexible connectors to accommodate these bends by permitting compression in the axial direction.
Due to the often near-continuous use of screening machines, the components must withstand cumulative wear and tear. The feed chute and the screen may be made from rigid material, such as metal; however, the connector must be made from bendable material, such as rubber, which is not as durable. The connector is also subjected to the effects of constant gyration. For those machines in which the flexible connector routes the particles along a curved path, some portions of the inside walls of the connector will bear the abrasive effects of free-falling particles passing through it toward the screen. Eventually abrasion from falling particles will wear a hole or split in the connector. Connectors can also fail simply from long-repeated flexing. These conditions require the occasional replacement of worn connectors.
In the past, connectors for screening machines have generally comprised some form of corrugated rubber or fabric sleeve roughly similar to the flexible hose used with a vacuum cleaner. These sleeves have been formed as one piece. When need arises for replacement of the connector, the entire sleeve must be replaced and discarded, regardless of whether replacement was necessitated by excessive wear at only one or two points along the connector. While some replacement of worn parts is necessary, and is therefore to be expected, this replacement and disposal of an entire length of connector due to excessive wear at only one or two particularly troublesome spots constitutes a waste of material and an increase in maintenance costs.
Furthermore, manufacturing capabilities are limited by one piece molding because each desired diameter of connector is required to be formed from a mold having that same diameter. The same limitations are true with respect to the length of the connectors. However, rather than bearing the additional and disproportionate expense required by the forming of a new mold, most screening machine manufacturers simply accommodate their machines to one of the standard diameters or lengths already used in the industry. This is not an optimum solution. The screening process for some applications would benefit from a variation in the diameter or the length of connector.
It is therefore an object of this invention to provide a connector for screening machines which does not require replacement of the entire length of connector due to wear and tear at only one area along its length.
It is another object of this invention to provide a connector which is better able to withstand the abrasive effects caused by particles passing therethrough.
It is still another object of this invention to provide a connector which is more easily manufactured in different diameters or lengths as may be needed for different installations.